"Traumatized and devastated", the gamer added.
Neighbors of Katz home, where he stayed with his parents, said they rarely saw or talked to him.
"He was weird all weekend, I mean he had shades on, he just - he didn't speak to anybody", the man said.
The gunman, Katz, was a professional gamer himself.
"Hes a well-known competitor", said one gamer to WFOX-TV, who claimed to have beaten Katz on Saturday.
Williams said that wounded victims are expected to recover. He's not here for the experience, he's not here to make friends.
Katz won a "Madden" championship in 2017 and his intensity was on display when he was interviewed by former National Football League star Steve Tasker, who asked about his placement as a No. 7 seed.
" Katz had previously won several tournaments and boasted of his prowess in an interview posted to YouTube".
Court records obtained by The Associated Press show that a man accused of killing two people and then himself at a video gaming competition in Florida had been hospitalized for mental illness. Apparent gunshots can be heard in recordings from the tournament on the bar's Twitch account, which was streaming the competition.
Drini Gjoka, one of the two competitors shown in the live stream, tweeted following the event. One person was taken to Baptist Medical Center with a minor injury. Tonight Electronic Arts CEO Andrew Wilson released a statement saying "We are committed to supporting Taylor and Elijah's families through this hard time, and we send our deepest sympathies to their loved ones, to those injured yesterday, and everyone affected".